John Mersch, MD, FAAP

Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Juvenile idiopathic arthritis (JIA) facts

Epidemiologic studies estimate that approximately 294,000 American children
are affected by JIA.

Children of European ancestry are more likely to develop
the condition while those of Japanese and Filipino background are less likely.

When considering the manifestation options of JIA, those children with European
background are more likely to experience the oligoarticular version of JIA (see
below) while those of African-American heritage are more likely have the rheumatoid
factor (RF) positive, polyarticular version (see below).

Among Caucasian
children developing oligoarticular JIA, younger girls (2-4 years of age) are
the most commonly affected.

The various epidemiologic patterns provide strong
evidence of genetic influences for both the development of JIA as well as the
clinical manifestations that may affect a child.

What is juvenile idiopathic arthritis?

Juvenile idiopathic arthritis (JIA) is the umbrella term under which several
forms of chronic arthritis in children are categorized. Regardless of type, all
of these conditions have several historical and/or clinical characteristics in
common. One or more joints must demonstrate evidence of inflammation
characterized by swelling of the joint area, limitation in the range of motion
of the involved joint(s), tenderness when the joint is moved, and increased
warmth of the joint region. These symptoms must be present (even intermittently)
for at least six weeks and affect a child less than 16 years of age.

JIA is the most frequent chronic rheumatologic disease of childhood, and the cause(s) are not well understood. Both environmental and genetic influences are
felt to contribute to the development of signs and symptoms of JIA.
Knowledgeable specialists (pediatric rheumatologists usually affiliated with
pediatric teaching hospitals) can help to limit the possibility of complications
of juvenile idiopathic arthritis including leg-length discrepancy, joint
contractures, and destruction and blindness due to inflammation of the eye (iritis).

Until the late 1990s, JIA was known in the U.S. as JRA (juvenile rheumatoid
arthritis) and JCA (juvenile chronic arthritis) in Europe. The revised name was
devised in order to better distinguish the childhood disease from rheumatoid
arthritis (RA) that affects adults. This new nomenclature has enabled the
categorization of six JIA subtypes. This updated classification has helped to
foster better communication among those doing research on causation, clinical
manifestations, and therapy of JIA.

JIA is considered a diagnosis of exclusion; the diagnosis can only be
confidently made when (1) the patient's history, physical exam, and laboratory
findings are consistent with those described in the literature by the
International League of Associations for Rheumatology and (2) other conditions
have been excluded. These include infection, malignancy, trauma, reactive
arthritis, immunodeficiency, and connective tissue/rheumatologic diseases (for
example,
systemic lupus erythematosus).

What are causes and risk factors of juvenile idiopathic arthritis?

While no specific cause(s) of JIA have been determined, there is strong
evidence of both genetic and environmental factors being implicated in the
development of the disease. Studies of the frequency of JIA have shown that if
one identical twin develops the disease that the likelihood of their identical
sibling developing JIA is 25%-40%. Studies of nonidentical siblings show
evidence that if one child develops JIA there is a 15 to 30 times increased risk
that a sibling will develop the condition when compared to the general pediatric
population.

The biologic and clinical manifestations of JIA provide strong evidence that
a general theme of an immune system misdirection is evident. The immune system
has two "arms" -- the cell based (lymphocytes, etc.) and humeral based
(antibodies). Rheumatologists have demonstrated that both of these elements of
the immune system react against the patient's own body structures (joints,
muscles, eye tissues, etc.). Much research is currently focused in an effort to
better understand this autoinflammatory process in the hope that understanding
the cause of JIA will enable better and more effective treatments and ultimately
a cure for the condition.

Rheumatoid Arthritis Diet

Persons with inflammatory arthritis, such as rheumatoid arthritis, may benefit by taking the omega-3 fatty acids that are in the oils of fish, particularly salmon. Those with osteoarthritis might benefit from the food supplement glucosamine.